This invention relates to a valve seat for a valve closure element for control of fluid flow within a valve. In particular, this invention relates to a valve seat effective over a wide temperature range which has a ring-type seal assembly compressibly closed by pressing of a ball valve.
A tubular-type sealing ring is disclosed in U.S. Pat. No. 3,515,371. In this patent a valve is described similar in operation to U.S. Pat. Nos. 2,076,840, 2,076,841, 2,516,947 and 2,719,022. In operation, such valves have a valve core which is caused to axially rotate from a full open position to a position wherein a solid portion of the valve core is positioned opposite a valve seat with subsequent pivotal movement of the core causing seating engagement with the seat. In U.S. Pat. No. 3,515,371 , this movement is caused by the synchronized rotative movement and axial movement of the valve stem cooperatively with the valve core.
In U.S. Pat. No. 3,515,371 a valve seat is described having an inner ring having a recessed portion at one end thereof about which a circular length of stainless steel tubing is positioned. An outer ring is adapted to abut against the tubing insert when assembled. The assembly is press fit between the inner ring and the outer ring, the assembly being such that the front surface of each are flush prior to machining. After machining, a seating face is created, including upper and lower lip portions respectively which act as a secondary seating surface for the valve core, supplementing the surface of the exposed tubing insert.